#ifdef NACHIA
#define _GLIBCXX_DEBUG
#else
#define NDEBUG
#endif
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(i64 i=0; i<i64(n); i++)
const i64 INF = 1001001001001001001;
template<typename A> void chmin(A& l, const A& r){ if(r < l) l = r; }
template<typename A> void chmax(A& l, const A& r){ if(l < r) l = r; }
using namespace std;




void testcase(){
    i64 N; cin >> N;
    vector<i64> A(N); rep(i,N) cin >> A[i];
    sort(A.begin(), A.end());
    vector<i64> B = A;
    B.erase(unique(B.begin(), B.end()), B.end());
    vector<i64> C(B.size());
    for(i64 a : A) C[lower_bound(B.begin(), B.end(), a) - B.begin()] += 1;
    i64 ans = 0;
    rep(i,C.size()){
        i64 a = B[i];
        i64 q = lower_bound(A.begin(), A.end(), a*2) - A.begin() - 2;
        ans += C[i] * (C[i]-1) / 2 * q;
        ans -= C[i] * (C[i]-1) * (C[i]-2) / 2;
    }
    cout << ans << "\n";
}

int main(){
    ios::sync_with_stdio(false); cin.tie(nullptr);
    testcase();
    return 0;
}